Nanoparticles of silver, MgO, ZnO, Fe3O4, ZnS, CuO and SnO2 have assumed great importance in view of their application in biomedical and bio technology, pollution abatement, biosensor technology and as agents of antimicrobial therapy. Several ways and means have been pioneered in the recent past, particularly, towards the production of nanoparticles of various metals individually and in combination. Nanosilver is fascinating owing to its antimicrobial activity useful in the process of reducing microbial contamination in the field of food processing and hygiene control. In the production of nanoparticles use of less toxic or non-toxic chemicals has always been preferred in the form of reducing agents and stabilizers as chemically green procedures are preferred over conventional synthesis.
Microorganisms cause mild to severe infections in human beings, animals and plants. Among the inorganic antimicrobial agents silver is a well known broad-spectrum agent employed most extensively since ancient times to fight infections caused by bacteria, yeast, fungi as well as virus. Nanosilver is known to inhibit or inactivate microorganisms effectively with lower toxicity to tissue. Due to the large surface area and high reactivity nanosilver is endowed with remarkable antimicrobial property. Because of long lasting biocidalaction nanosilver preparations are currently being used as antimicrobial agents in several industries such as ceramics, paper, plastic and packing films.
Cellulose is a biopolymer mostly produced by plants and micro-organisms, however some marine animals were also shown to produce cellulose. Though wood is the major source of plant cellulose its separation and purification is a tedious process with the intervention of toxic chemical, hence, its large-scale application in pure form is impracticable. Bacterial cellulose produced by Acetobacter xylinum (Gluconacetobacter xylinus) is an attractive biomaterial with its intrinsic nanostructural hierarchy, its purity, mechanical strength and chemical robustness. This bacterium produces extracellular cellulose under static culture condition in the form of highly reticulated net like structure along with the entrapped bacteria, media components and protein. The whole complex is referred to as pellicle. The cellulose is purified using alkali treatment at boiling temperature. In the present investigation we have attempted to develop a novel antimicrobial composite material comprising of bacterial cellulose and nanosilver. Several researchers have reported the use of plant cellulose in the preparation of antibacterial silver formulations. We report the preparation of silver nanoparticles embedded into nanoparticulate bacterial cellulose as stabilizer for effective inhibition of Staphylococcus aureus. The process is simple and scalable for its real-time applications in various fields such as food packaging and in antimicrobial therapy.